Generally, an electric power converter that, drives an alternate current (AC) load at an arbitrary frequency includes a main circuit unit and a control unit. The main circuit unit includes a switching unit that performs switching from a direct current (DC) voltage (which includes a DC voltage generated from an AC voltage) to an AC voltage having an arbitrary frequency and that outputs the AC voltage. The control unit controls a switching element that is a component of the switching unit based on information concerning the operation of a preset load and information transmitted from various detectors included in the main circuit unit so that the switching element reaches a desired ON/OFF operational state.
Electric power converters that perform open-loop control with ease or products that perform closed-loop control with high accuracy so that a user can use the product in a control manner according to a purpose are available. These products are prepared for various powers ranging from small power of several watts to large power of several thousand kilowatts. Thus, flexible responses can be offered to the diverse needs of users. The control manner according to a purpose is realized by the control unit. The necessary power is realized by the main circuit unit.
In the electric power converter, characteristics of the main circuit unit, calibration values of various detectors provided in the main circuit unit, production history such as manufacturing date, operation history, specifications in addition to information concerning the operation of a load, are needed as initial values prepared beforehand for realizing a desired function. Herein, let characteristics of the main circuit unit, calibration values, a production history, an operation history, and specifications be called management information concerning the main circuit unit.
In a conventional electric power converter, a control unit includes a storage unit that stores information, such as that concerning the operation of a load, and hence management information concerning a main circuit unit is also stored in the storage unit included in the control unit.
Therefore, conventionally, the main circuit unit and the control unit are kept in a separated state from each other, and there is a need to store management information concerning the main circuit unit in the control unit when the main circuit unit and the control unit are combined together for shipment. Likewise, when the main circuit unit and the control unit, which have been separated from each other after having been combined together, are again combined together, there is a need to store management information concerning the main circuit unit in the control unit. Therefore, the combining work is troublesome.
When a change in function between a product that performs easy open-loop control and a product that performs highly accurate closed-loop control is made by changing the control unit into another, there is a need to temporarily upload management information concerning the main circuit unit to another storage device and then download the information to the newly provided control unit. Therefore, the function changing work is troublesome.
Usually, to advance the delivery date, products are beforehand produced and stored. However, conventionally, the main circuit unit and the control unit have been required to be produced in a one-to-one relationship, and hence the electric power converter has been required to be produced and stored for each capacity and in each control manner. This has caused an increase in the volume of inventories.
A possible solution to solve the problem is to provide a storage unit that stores management information concerning the main circuit unit in the main circuit unit. With respect to the solution, for example, Patent Document 1 discloses a head-separation type camera in which a camera head and a camera control unit that controls the camera head are detachably connected together, and the camera head is provided with a storage device that stores various data concerning the camera head, and the control unit stores the usage condition of the camera head in the storage device.
Additionally, for example, Patent Document 2 discloses an industrial-use robot in which the main body of the robot is provided with a model data setting unit, and a control unit determines the start of control based on consistency with the model data.
However, a difference lies between the significance of providing the storage unit in Patent Documents 1 and 2 and the significance of providing the main circuit unit with the storage unit in the present invention. Additionally, the conventional devices (Patent Documents 1 and 2) and the present invention are different in the character of information to be stored.
The Patent Documents 1 and 2 are as follows.
Patent Document 1: Japanese Published Unexamined Patent Application No. 2002-354300
Patent Document 2: Japanese Published Unexamined Patent Application No. H6-190762
This invention has been made in consideration of these circumstances. It is therefore an object of the present invention to provide an electric power converter capable of facilitating the combining work for combining a main circuit unit and a control unit together and the function changing work and capable of restricting an increase in the volume of inventories.